1. Field of the Invention
This invention relates to pipe cutters, more specifically to pipe cutters adapted to be inserted into the interior of pipes, and more particularly to pipe cutters having a single cutting blade, and further having guidance means to insure that a pipe will be cut on substantially perpendicular to the longitudinal axis of the pipe.
2. Description of the Prior Art
Early attempts to cut pipe involved the mere use of sawing tools. These manual tools require the user thereof to begin sawing a pipe on its exterior surfaces. Considerable difficulty is encountered when hand held saws are used to cut pipes. It is very difficult to make a level cut, it is even more difficult to make such a cut flush with a surface, and it is impossible to make such a cut beneath a surface.
For example, in the art of installing domestic toilets, it is desirable to obtain a level cut on a 4" PVC (polyvinylchloride) pipe, and the cut may need to be flushed with the floor of the room in which the toilet is being installed.
If the pipe leading to the toilet has been installed too close to, or too far from, a wall, it is necessary to connect the said improperly disposed pipe to an offset flange, so that the toilet can be installed in its proper location. When it is necessary to use such an offset flange, the pipe leading to the toilet must be cut below the surface of the floor of the room in which the toilet is being installed. The hand held saws of the prior art are utterly incapable of cutting a pipe below a surface from which the pipe protrudes.
Therefore attempts have been made to provide pipe cutters capable of cutting a pipe below the surface from which it protrudes. One attempt involves the provision of a plurality of cutting blades which are radially mounted about a housing which is lowered into the interior of the pipe. These devices suffer from the fact that their blades often cut different levels of the pipe. In other words, if four cutting blades are provided, the four peripheral cuts often do not coincide. The pipe is eventually cut by the four blades, but the resultant cut is unlevel and mangled.
The earlier devices have used springs to cause the expulsion of the retracted cutting wheels from their housing. These mechanisms are easily worn, unreliable, flimsy and uneconomical to produce.
The known devices possess another serious shortcoming. If access into the interior of a pipe is denied at one end thereof, for example, when a pipe is projecting upwardly from a floor surface, the earlier devices are incapable of cutting off a minimum length of piping. An example of a pipe cutter lacking the ability to cut minimum lengths of pipe in this situation is a pipe cutter model produced by the Breeze Company. In this cutter, the blades must be inserted at least two inches into the interior of the pipes before any projecting length can be removed. Thus, if less than two inches of protruding pipe are desired to be removed, the only known earlier device capable of doing the job is the hand held saw.